The mechanoelectrical response of the cytoplasmic membrane of Vibrio cholerae.
The mechanoelectrical response of the cytoplasmic membrane of Vibrio cholerae.
复制标题
霍乱弧菌细胞质膜的机电响应。
DOI：
10.1085/jgp.201310985
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发表时间：
2013
期刊：
影响因子：
--
通讯作者：
Sukharev,Sergei
中科院分区：
文献类型：
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作者：
Rowe,Ian;Elahi,Merina;Huq,Anwar;Sukharev,Sergei
霍乱弧菌在盐度波动的沃茨中的持续存在依赖于这种兼性肠道病原体适应不同渗透条件的能力。在渗透压降低的情况下，细菌内积累的渗透压调节剂可以通过张力激活的通道快速释放。采用新建立的V.在大肠杆菌中，我们首次对其细胞质膜进行了膜片钳表征，并将其张力激活电流与大肠杆菌进行了比较。饱和压力斜坡显示了两个激活波，属于小电导（MscS）样通道的Msc 1-nS机械敏感通道和大电导（MscL）样通道的Msc 3-nS机械敏感通道，压力中点比p0.5MscS/p0.5MscL为0.48。我们发现，MscL样通道inV。霍乱弧菌的密度比大肠杆菌高3倍。然而，这些弧菌对大的渗透压下降冲击的耐受性较低。VibrioMscS样通道在去极化电压下表现出特征性的内向整流和亚导电状态;它们也在亚饱和张力下适应和整流，并在张力释放后2秒内恢复，就像E一样。coliMscS.海藻糖是一种在高渗条件下积累的相容性内部渗透剂，它使MscL和MscS样通道的激活曲线向更高的张力方向显著移动，但不能自由地分配到通道孔中。V.霍乱提供了新的途径，在原位分析膜组件的渗透存活和产电运输在这种病原体的关键。
Persistence ofVibrio choleraein waters of fluctuating salinity relies on the capacity of this facultative enteric pathogen to adapt to varying osmotic conditions. In an event of osmotic downshift, osmolytes accumulated inside the bacterium can be quickly released through tension-activated channels. With the newly established procedure of giant spheroplast preparation fromV. cholerae, we performed the first patch-clamp characterization of its cytoplasmic membrane and compared tension-activated currents with those inEsherichia coli. Saturating pressure ramps revealed two waves of activation belonging to the ∼1-nS mechanosensitive channel of small conductance (MscS)-like channels and ∼3-nS mechanosensitive channel of large conductance (MscL)-like channels, with a pressure midpoint ratio p0.5MscS/p0.5MscL of 0.48. We found that MscL-like channels inV. choleraepresent at a density three times higher than inE. coli, and yet, these vibrios were less tolerant to large osmotic downshocks. TheVibrioMscS-like channels exhibit characteristic inward rectification and subconductive states at depolarizing voltages; they also adapt and inactivate at subsaturating tensions and recover within 2 s upon tension release, just likeE. coliMscS. Trehalose, a compatible internal osmolyte accumulated under hypertonic conditions, significantly shifts activation curves of both MscL- and MscS-like channels toward higher tensions, yet does not freely partition into the channel pore. Direct electrophysiology ofV. choleraeoffers new avenues for the in situ analysis of membrane components critical for osmotic survival and electrogenic transport in this pathogen.